The invention relates to a slide gate nozzle or shut-off control valve to be mounted in a wall or lining of a vessel containing, in particular, molten metal and including at least two refractory shut-off parts that are provided with passages or openings, that project into the vessel interior and that have respective sliding surfaces that can be displaced sealingly relative to one another. The invention also relates to refractory shut-off parts for such nozzle or valve.
A final control supply element of the above described category is disclosed in German DE-P 35 40 202 and substantially comprises two concentric tubes or pipes that project into the vessel, that can be moved therein relative to one another and that have openings through which the melt passes. The openings of the pipes can be brought more or less into alignment or coincidence by means of axial lifting movement and/or rotary movement. Thus, it is possible to correspondingly regulate the volume of molten metal discharge. The two refractory pipes must be machined quite accurately in the surface regions thereof that are in contact with each other in order to obtain an absolute seal. The machining of these cylindrical rotational surfaces is, therefore, relatively time-consuming. In addition, the risk of breaking the pipes off during assembly and also during operation is relatively high due to possible generation cross forces.